As companies rely more and more on e-commerce, online transaction processing, and databases, the amount of information that needs to be managed and stored can intimidate even the most seasoned of network managers.
While servers do a good job of storing data, their capacity is limited, and they can become a bottleneck if too many users try to access the same information. Instead, most companies rely on peripheral storage devices such as tape libraries, RAID disks, and even optical storage systems. These storage devices are effective for backing up data online and storing large amounts of information. By hanging a number of such devices off of a server, a network administrator can create a server farm that can store a substantial amount of data for the enterprise.
But as server farms increase in size, and as companies rely more heavily on data-intensive applications such as multimedia, this traditional storage model is not quite as useful. This is because access to these peripheral devices can be slow, and it might not always be possible for every user to easily and transparently access each storage device.
Recently, a number of vendors have been developing Storage Area Network (SAN). SANs provide more options for network storage, including much faster access than the peripheral devices that operate as Network Attached Storage (NAS) and SANs further provide flexibility to create separate networks to handle large volumes of data.
A SAN is a high-speed special-purpose network or subnetwork that interconnects different kinds of data storage devices with associated data servers on behalf of a larger network of users. Typically, a storage area network is part of the overall network of computing resources for an enterprise. A SAN is usually clustered in close proximity to other computing resources such as IBM S/390 mainframes but may also extend to remote locations for backup and archival storage, using wide area network carrier technologies such as ATM or Synchronous Optical Networks. A SAN can use existing communication technology such as optical fiber ESCON or Fibre Channel technology.
SANs support disk mirroring, backup, restore, archival, and retrieval of archived data, data migration from one storage device to another, and the sharing of data among different servers in a network. SANs can incorporate subnetworks with network-attached storage systems.
Although SANs hold much promise, they face a significant challenge. Bluntly, consumers expect a lot of their data storage systems. Specifically, consumers demand that SANs provide network type scalability, service, and flexibility, while at the same time providing data access at speeds that compete with server farms. This can be quite a challenge, particularly in multi-server environments. In these environments, a client wishing to access specific information or a specific file is redirected to a server that has the piece of the requested information or file. The client then establishes a new connection to the other server upon redirect and severs the connection to the originally contacted server. However, this approach defeats the benefit of maintaining a long-lived connection between the client and the initial server.
Another approach is “storage virtualization” where an intermediary device is placed between the client and the servers, with the intermediary device providing the request routing. None of the servers is hereby aware that it is providing only a portion of the entire partitioned service. Adding the intermediary device adds complexity to the system.
It would therefore be desirable to provide a method and system that allows a client to contact any server in a multi-server environment and to access resources distributed with a reduced reliance on an intermediary device or server.